Do you mean look it up based on the number inscribed in the ring? I don't know of a way to do that other than contacting Tiffany. The preowned Tiffany ring I bought was from back in the time where they were still GIA certified as well.
Correct, I’d like to look up the specifications based on the inscribed number, but it doesn’t look like they have a search portal where you can look it up. Just wondering if anyone knows if there’s someone you can call or somewhere you can take it to be searched.